Borax-ferricyanide demonstrates which tissue component?

• A. Myelin
• B. Nissl substance
• C. Astrocytes
• D. Glial fibers

Answer: (A)

This stain is used to visualize myelin, the lipid-rich sheath around many nerve fibers. It interacts with the lipid components in myelin, producing a distinct color that highlights white matter and helps reveal demyelination or changes in myelin integrity.

Nissl substance, by contrast, is the rough endoplasmic reticulum in neuron cell bodies and is best seen with basic dyes like cresyl violet, not this stain. Astrocytes and glial fibers are typically shown with other stains or immunostains that target intermediate filaments or specific glial proteins, not borax-ferricyanide.